Here's a miraculous journey that continues to leave scientists scratching their heads. The monarch butterflies that appear at Sierra Chincua Butterfly Sanctuary in Angangueo, Mexico, have journeyed as far as some of the tourists have -- Canada, Wisconsin, New York, Pennsylvania and other far-off areas. And, they've never been to this mountainous region in the Mexican state of Michoacan. Yet more monarchs come back every year, half a billion or more arriving around the Mexican Day of the Dead in early November. No one knows how they navigate -- whether they use visual cues, some sort of magnetic orientation, light or a combination of the sun, moon and stars. But their global positioning systems are right on target and the closer they get to Mexico, the more their various pathways begin to converge like rush hour at an airport. They gather in the forests between 10,000 and 12,000 feet high in the Transverse Volcanic Mountains and hibernate for several months. Here's incredible pictures of their journey. -- Meg Jones | Milwaukee Journal SentinelMeg Jones | Milwaukee Journal Sentinel